ice volcano
Ice Volcano

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Where is Lake Superior and the Keweenaw Peninsula?

Ice Volcanoes of Lake Superior's South Shore

Photos and Website Originally Created by Michael Dolan and Paul Kimberly

Disclaimer: Our comments about the research.

Ice Volcanoes of Lake Superior's South Shore: Preliminary Observations and Hypotheses

Ice volcanoes commonly occur during the winter months along the north shore of Lake Superior. Cones begin to form at the leading edge of the ice shelf as it builds out into the lake. When the waves, driven by strong onshore winds, feel bottom they build and break onto the ice shelf. After the ice shelf has built out, waves continue to travel underneath the ice and are forced up through cracks and previously formed cones.

In this page, we will present the conditions (1-3) neccessary for the phenomenon to occur. We will also discuss the formation (4-5) and resulting physical characteristics (6-8) of the ice volcanoes

1. High Surf

The intensity and location of "eruptive" activity is primarily controlled by wave height and direction. In our estimate, waves with amplitudes less than one meter are too small for cone generation. Activity is best when high onshore winds are present, typically originating from snow squalls and regional storms. However, not all onshore winds create proper wave conditions.

2. Formation of Ice on the Lake

Ice forms on the lake8-bit JPG 24-bit JPG Ice forms on the lake.

The temperature and conditions of the lake surface must be conducive to the formation of ice.

3. Ambient Air Temperature

For cones to build, ambient air temperatures must be several degrees (unmeasured) below freezing. "Eruptions" occuring at temperatures at or above freezing will cause degredation of the cone.

4. Waves Hitting the Leading Edge of Ice Shelf

Leading edge of thick ice shelf 8-bit JPG 24-bit JPG Leading edge of thick ice shelf.

High surf slamming against the face of the ice shelf may result in cone formation. Waves energy can concentrate in small valleys, splashing onto the shelf.

5. Geomorphologic Features Causing Waves to Swell

Ice built up along a rock reef 8-bit JPG 24-bit JPG Ice built up along a rock reef.

Three geomorphologic features of the lake floor have been recognized in conjuction with cone formation; 1. shoreline 2. sand bar 3. rock reef.

  1. shoreline
    Activity at the shoreline occurs when the ice shelf first forms. Waves approaching the shoreline feel bottom, swell and crash onto the shore. Chunks of ice and lake-spray (spatter) help create a raised ice shelf along the shoreline. Irregularities along the leading edge of the shelf help concentrate wave energy into larger waves, thus creating taller ejections of spatter. It is at the irregularities that ice volcanoes typically form.
    Cones at the leading edge are normally open to the water, however after the ice shelf has built away from the volcanoes the cones may remain active and become completely enclosed. Wave energy beneath the ice forces water up through cracks, openings and previously formed cones as the wave feels bottom.
    Occurance of cones along any particular shoreline is dependant upon offshore bathymetry. Bays or shorelines protected by offshore rock reefs and/or sand bars rarely receive enough wave energy to create ice volcanoes.

  2. sand bars
    The same phenomenon described for shorelines generally occurs as the prograding ice shelf reaches a sand bar. At this point the progradation of the ice shelf is retarded due to the increased energy of the breaking waves. The ice sheet provides a surface for spatter to collect and coalesce. Sand bars are generally surrounded by slightly deeper water than shorelines, creating conditions for larger cones (discussed below).

  3. rock reef
    Two types of rock reefs are observed: 1. subaqueous 2. subaerial

    1. Subaqueous
      Cones forming at subaqueous reefs exhibit the same behavior as those at sand bars.
    2. Subaerial
      The subaerial reefs acts similar to the leading edge of the ice shelf. Spatter from the breaking waves coalesce, extending the height of the reef. Irregularities in the reef concentrate wave energy accentuating the process. It is not necessary for the backwaters to be frozen prior to cone formation.

6. Morphology

10 meter high ice volcano 8-bit JPG 24-bit JPG 10 meter high ice volcano.

Ice volcanic cones range in size from less than one meter to greater than 8 meters in height, measured from base to peak. The largest cones typically occur in areas exposed to high energy waves (offshore sand bars and rock reefs).

breached ice volcano 8-bit JPG 24-bit JPG A view from the lake of a breached ice volcano.

Symmetrical unbreached cone 8-bit JPG 24-bit JPG Symmetrical unbreached cone.

Only two shapes of cones (shield volcano and stratovolcano) have been observed to exhibit two forms of symmetry (breached and unbreached). Observations to date do not reveal relationships between size, shape and symmetry. However, the formation of cones can be related to symmetry. Cones forming on the leading edge of the ice shelf are breached in the lakeward direction. "Eruptions" occuring landward from the shelf's edge form unbreached cones.

7. Arcs

evenly spaced ice volcanoes8-bit JPG 24-bit JPG Arc of evenly spaced ice volcanoes along a rock reef.

shield and stratovolcanoes of ice8-bit JPG 24-bit JPG Two arc sets composed of shield and stratovolcanoes of ice.

Ice volcanoes are prototypically aligned in arcs that follow the strike of the associated geomorphologic features (shorelines, sand bars and rock reefs). Cones contained with in the arcs are usually evenly spaced, however, random spacing is not uncommon. Successive arcs will form in areas that contain parallel assemblages of sand bars. Cones comprising the arcs display a lakeward increase in size.

8. "Cold Spot" Ice Volcanoes

"Cold spot" ice volcanoes are nearly symmetrical single cones that apparently are not related to shoreline, sand bar or rock reef arcs. We have designated them "cold spot" volcanoes due to their solitary existance. They occur near shore and are apparently associated with zones of weakness in the ice. "Cold spot" ice volcanoes have yet to be observed in their active state.

More Pictures of Ice Volcanoes

Questions? or Comments!

From the Geological & Mining Engineering & Sciences Dept.
Visit these web sites:

Aurora Page: A collection of the best links and a great image archive of the Aurora Borealis:
Volcanoes Page:One of the top sites for volcano information

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or the Michigan Mining History links. Visit the archival photos of historic mines in Michigan where many of the gems and minerals came from: Mine Shafts of Michigan

Modified on February 7, 2011
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Department of Geological/Mining Engineering & Sciences
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